INSTITUTE, PUSA, FOR 1918-19 71 



During the season 1918 a series of field experiments 

 was carried out with the object of throwing some light on 

 the condition affecting the spread of the disease. The 

 results were not so definite as was hoped, the experiments 

 suffering considerably from the abnormal monsoon of 1918, 

 but suggested that the spread of the disease through spores 

 mingled with the seed was not an important means of disse- 

 mination. In this case it may not be necessary to persist in 

 the steeping of the Bihar seed crop in a disinfectant. As 

 a precautionary measure, however, the treatment with 

 copper sulphate was carried out this year with some 40 

 tons of seed grown in Bihar. 



While working on the black band disease of jute, a 

 number of cases of disease due to infection with the sclero- 

 tial fungus previously identified as Rhizoctonia Solani 

 Kiihn were met with. It is by no means uncommon in the 

 field for both this fungus and D. Corchori Syd. to occur on 

 the same plant, and at first the natural tendency was to 

 assume that all the pycnidia which were so frequently found 

 associated with the sclerotial fungus were immature 

 pycnidia of D. Corchori. In 1917 some jute plants were 

 infected with pure cultures of R. Solani and all the plants 

 became diseased and died. Upon the diseased portion of 

 the stem small black pycnidia appeared. As these infec- 

 tions were carried out on plants in a field in which D. Cor- 

 chori was rampant, it was thought that we had here a case 

 of a natural infection with D. Corchori superimposed 

 upon the artificial inoculation ; a brief microscopic examin- 

 ation showing a condition which was considered to be 

 immature D. Corchori. In 1918 observations at Dacca 

 showed some cases of disease due to R. Solani in which the 

 infection had obviously commenced at a point 2-3 feet 

 above the ground level, and at the time it was by no means 

 plain how a fungus which was only known in a sclerotial 

 form succeeded in establishing itself in this way. More- 

 over, these specimens and other similar cases in the Pusa 

 crop also showed a pycnidium on the outer surface. These 

 pycnidia and those occurring on the infections of 1917 



